I believe that the soft plastic just looks better to the fisherman, that's why so many keep buying them.

In my first pic, the beautiful Micro Spoon plastic has beautiful eyes and a thin bouncy tail, while the woolybugger looks like a clump of feathers! But when you put them in the water, the plastic is only a small blob while the marabou and hackle pulsate and quiver like crazy and look so alive.